Polyspan on an i-beam

[Bill Sawyer]

Has anyone done this? I just wondered how it worked out. I recently bought some but have not tried it yet.

[Ralph Wenzel (d)]

A couple of years ago Sparky said that he'd never again use anything other than PolySpan on I-Beams.

Ralph

[SteveMoon]

I've used polyspan on an I-beam with great results. I love the ability to use
a heat gun to do final shrinking after the polyspan has been doped into place.

Steve

[tom hampshire]

I have used poly on several conventional wings (sheeted from L/E to spar, with capstrips and sheet T/E) and found it OK.  BUT it lacks strength compared to either silkspan or silk.  Puncture resistance is better than silkspan, about the same as silk, but it adds very little torsional strength/stiffness.  So it works well on a conventional wing where the structure, not the covering, provides the torsional stiffness.  I have not found it good at all when used on a non-planked wing, with top and bottom spars and open bays.  Steve, has your polyspan I beamer been flown in heavy turbulence?  I'd be hesitant to try it without some real world experience with flexing under heavy loads.  Certainly a stiffer structure penetrates turbulent air much better than a 'flexible flyer'.   Have you experienced this as well?  Tom H.

[John Miller]

It might be the time to point out that Gordan Delaney's 2 or 3 time Nat's winning classic, Collosuss, designed by Jim Tichey, an I-beam of about 700 sq inches, is finished with polyspan and dope.

[john e. holliday]

I have polyspan on my Sheeks Spitfire and see no problems other than the plane needs someone that knows how to fly it.  DOC Holliday